The present invention relates to a garage door having precise control for opening and closing and prompt reminder when maintenance is needed so that the safety of operation can be improved.
Please refer to FIG. 1. A garage door apparatus typically has two tracks 2a on both sides of a garage door 1a, respectively, so that the garage door 1a can move along the tracks 2a through rollers. Above the garage door 1a, there are a linking device 4a and a controller 3a. The linking device 4a includes a rail 41a with one end fixed on the wall and the other end connected to the controller, a rack 42a slidably attached to the rail 41 and a linkage 43a with one end connected to the garage door 1a and the other end connected to the rack 42a Accordingly, after the controller 3a receives user's command, the garage door can be opened or closed.
In order to prevent accidents, such as closing garage door 1a to injure people, usually a detecting device 5a that includes a single-beam transmitter unit 51a and a receiver unit 52a is installed near the ground at two sides of the garage door 1a, respectively. An electric wire 6a along the periphery of the garage door 1a connects the detecting device 5a and the controller 3a Thus, when an obstacle appears on the path to block the emitting beam at closing garage door 1a, the controller 3a can respond immediately to reverse or stop the operation of the garage door 1a to assure the safety.
Besides, the maintenance on garage door apparatus is usually carried out according to an estimate period of usage or a predetermined schedule. However, this may not assure a timely service when maintenance is actually needed according to the machine condition. Therefore, conventional method fails to work as a criterion to determine whether a required maintenance is due. Consequently, it may have safety concerns in use.
Altogether, the conventional garage door apparatus has disadvantages as follows.    1. The detecting device utilizes a single horizontal beam, so it only detects the obstacle at a certain horizon level. Thus, when it fails to detect the obstacle on other situations, a detection error will happen and an accident could happen. This design cannot assure safety operation.    2. The estimated or predetermined maintenance schedule fails to work properly to provide timely service. Therefore, safety concerns of use are existed.    3. The installation of the detecting device and the controller connected by the exposed wire is lousy and inconvenience. In addition, the exposed wire is easily damaged to cause maintenance problem and interruption of signal transmission. This aggravates the difficulty in safety control. On the other hand, exposed wiring affects aesthetics and tidiness for the garage.
Although U.S. Pat. No. 6,326,751 discloses a garage door with moving speed detection, its design is different from Applicant's invention and it cannot provide a prompt reminder for the maintenance to enhance the safety and prolong the life.